1. Field of the Invention
The present invention relates to a system for measuring electromagnetic properties of a member and, more particularly, to a system that does not physically contact the member while the property is being measured.
2. Prior Art
U.S. Pat. No.5,141,595 (Darling, Jr.) discloses a method and apparatus for coating fibrous refractory substrates with a highly uniform layer of graphite or other material. Electrical pick-ups are used with an electronic control and transport motor for physically altering substrate transport velocity, or other parameters, to adjust the coated substrate's properties.
U.S. Pat. No. 5,268,062 (Darling, Jr.), a continuation of Darling, Jr. '595, discloses the method and apparatus of Darling, Jr. '595 for coating rigid porous refractory substrates.
U.S. Pat. No. 4,408,156 (Veys) discloses the use of microwave radiation to detect thin conductive fibers placed on a sheet article of non-conductive material for identification purposes. The system computes the difference between transmitted and reflected radiation.
U.S. Pat. Nos. 4,500,835 (Heikkila) and 4,607,212 (Jakkula) disclose the use of microwave radiation for detecting grain direction and knots in lumber.
U.S. Pat. No. 3,818,335 (Stungis et al.) discloses use of probes to monitor and detect the applied amounts of conductive material on a moving non-conductive web. U.S. Pat. No. 2,940,040 (Rosenthal) discloses the measurement of direct current resistivity of plastic materials for quality control purposes.
U.S. Pat. No. 5,012,248 to Munro et al. discloses the measurement of the thickness of a radar absorbing coating by receiving reflected radio frequency energy from the coating through a dielectric impedance matching element which is physically placed against the coating.
"Nondestructive Microwave Scanning Measurements for Material Property Evaluation," by P. R. Wims and D. D. Palmer, Review of Progress in Quantitative Nondestructive Evaluation, Vol. 10A, Plenum Press, New York, 1991, describes a system for measuring properties of radar absorbing material by illuminating small volumes of a test sample with microwave energy while the specimen is maneuvered between two antennas by an automated translation stage.